Home > Publications database > Group IV (Si)GeSn Light Emission and Lasing Studies |
Book/Dissertation / PhD Thesis | FZJ-2019-02145 |
2019
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
Jülich
ISBN: 978-3-95806-389-1
Please use a persistent id in citations: http://hdl.handle.net/2128/21941
Abstract: To enable the continuous evolution of information technology, increasing data transferrates are demanded. This is accompanied by rising power consumption and requisition of larger bandwidths. The integration of photonics with electronic circuits provides a solution, which facilitates the decrease of heat dissipation and allows transmitting data in parallel with the speed of light, boosting the performance of integrated circuits. Such a concept is preferably realized within the highly elaborated silicon processing technology, on which the whole information technology is based on. The most pressing issue, missing for the fully integration of photonics to electronics, is an integrated light source. Silicon-germanium-tin (SiGeSn) alloys offer a promising extension of this platform, since they can be monolithically grownon Si and their direct bandgap in specific configurations was proven in 2015. This thesis summarizes studies on spontaneous and stimulated emission of GeSn alloys mainly based on photoluminescence (PL) and electroluminescence (EL) spectroscopy. The effect of strain relaxation in GeSn alloys, grown on top of Ge virtual substrates, on optical properties is investigated. The temperature trend of spontaneous emission provides insight on the contribution of non-radiative defect recombination. It also illustrates the indirect-to-direct bandgap transition in Ge$_{0.87}$5Sn$_{0.125}$ alloys under strain relaxation. Heterostructure PL analysis emphasizes the importance of defect engineering, since presence of defects close to the active layer heavily deteriorates light emission. To prove the concept of electrical carrier injection, GeSn-based LEDs are fabricated. Electroluminescence spectra unveil similar temperature dependent behavior as PL from unprocessed layers, with comparable defect-induced limitations. The examination of Ge and SiGeSn as barrier materials in multi-quantum-wells (MQWs) proves [...]
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